In recent decades, electrically driven pumps have gradually replaced conventional mechanical pumps, and have been widely used in heat circulating systems. The electrically driven pumps have various advantages, such as no electromagnetic interference, high efficiency, environmental protection, and stepless speed regulation, and can meet the requirements of the market well.
The electrically driven pump includes a rotor assembly and a stator assembly which are completely isolated by a partition, thereby avoiding an issue of liquid leakage in a conventional motor-type brushless direct-current water pump. Currently, the rotor assembly includes an impeller and a rotor, and the rotor assembly is generally formed integrally by injection molding, that is, the impeller and the rotor are made of the same material, the rotor is magnetized, and the impeller is not magnetized, which wastes the magnetic material, and the manufacturing cost is high. Furthermore, the magnetic material is brittle, which results in that the impeller has a low toughness and is apt to be damaged, and the manufacturing process is complicated.
Therefore, it is necessary to improve the conventional technology, to address the above technical issues.